There is not enough information provided to answer your question. Irregular and heavy periods are abnormal, and are worrisome especially given since they were normal before. The bleeding may be coming from the uterus, cervix, and/or vagina. Your mother should return to her doctor for additional tests, including but not limited to pelvic ultrasound.
I am sorry your mom is dealing with this especially with less access to health care. It's possible that the hormonal changes that precede menopause may be the cause of all this bleeding. And, unfortunately, perimenopause can last for years. Fibroids or polyps (benign growths) can also cause excessive bleeding. These growths can be removed (and the uterus and its lifelong functions preserved) if they continue to be problematic.
Is she no longer on the medicine she was prescribed last year that regulated her cycle? If not, maybe her doctor would prescribe it again. She is likely losing a lot of iron. If her levels are low or she has symptoms of iron deficiency, taking an iron supplement with vitamin C would be a good idea.
I hope this helps. Post back and let us know what you find out and how she's doing.